Mark orders as paid via spreadsheet or API

Hi

We need a way to be able to mark invoices as paid via a spreadsheet, we currently use xero for our accounts and can output a list of paid orders but then have to spend 1-2 hours a week marking the invoices in deco as paid using the record payment feature.

it would be great if you could create a basic import that we can upload that marks invoices as paid. the spreadsheet would only need to be basic like order number, paid amount. 

it would be a massive bonus if we could also do this via API :)

Many thanks 

Dan